[MPlayer-users] performance regression in xvid encoding between 1.0-pre6 and 1.0-pre7

[The Wanderer]

Marcin Slusarz wrote:

> On Mon, Jul 25, 2005 at 08:45:31PM +0200, Guillaume POIRIER wrote:
> 
>> On 7/25/05, Marcin Slusarz <mslusarz at alan.umcs.lublin.pl> wrote:
>> 
>>> hi after upgrading mplayer to 1.0-pre7 i noticed that encoding
>>> with mencoder is really slow. as i usually record and encode
>>> straight from the tv card and cpu load is at 96-99%, 60%
>>> regression is "noticable" ;) here are results from testings:
>> 
>> I changed xvid defaults to improve default quality. Either go back
>> to last defaults (look at the man page of -pre6 for that) or look
>> at our xvid encoding guide (in the HTML docs) to see what options
>> can be disabled safely to improve speed.
> 
> thanks for the answer. i found that these options are: vhq=0,
> nochroma_me, notrellis (and bvhq=0 but this does not impact
> performance).
> 
> it would be nice if every option would have small marker - eg. +q as
> "improves quality" and +s as "improves speed".

While the latter might be possible, the former is not, since the same
options which improve quality in some cases can often worsen it in
others. I'm not entirely sure, but I think that most of the ones which
always improve quality are already marked that way, albeit not in such a
quick-glance-friendly "flag" kind of way.

> another thing that might be improved in the docs are "defaults" -
> they are missing in many places which makes a bit difficult choosing
> right options...

This does sound like it would be useful, and a somewhat cursory look at
the man page seems to indicate that such defaults are in fact not
provided in some cases. I may have some free time in the near future;
I'll try to have a look at it, see what people can turn up.

> ps: there is a tiny mistake in vhq description - 0 and 1 are marked
> as default

Where? In the man page? I just checked my own copy (CVS version), and 1
is marked as the default; 0 is simply listed as "off". I don't know
offhand whether or not this is different in the 1.0pre7 release, but if
there is a difference the problem has been fixed since.

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

A government exists to serve its citizens, not to control them.